N'otes on North American Crustacea. 183 



Pericera diplacantlia, nov. sp. 



Body pubescent and provided with curled hairs above as in P. sub- 

 parallela. ? Carapax subtrigonal, narrow ; back protuberant. Lateral 

 process or spine rather long, and double, seeming to consist of two 

 spines, one above the other, connected nearly to their tips by a web-like 

 connecting lamina, concave anteriorly, convex posteriorly. Antero- 

 lateral margin concave, unarmed except with a small hepatic tubercle. 

 There are five conical tubercles on the posterior half of the back, and a 

 few minute ones interspersed. Gastric region strongly inclined anteri- 

 orly, with the frontal region. The rostrum forms nearly one-third the 

 length of the carapax ; horns very long, slender, cylindrical, acute, diver- 

 gent, but at base connected by a web-like lamina for one-fifth their 

 length. The anterior spine of the basal joint of the antenna? is very 

 minute, not seen from above. Orbital tubes moderately protuberant; 

 praeorbital tooth obtuse and not prominent. Length of the carapax in a 

 female, 1.08 ; breadth, spines included, 0.8, spines not included, 0.55 inch. 



It is similar in general character to P. subj)arallela, but 

 easily distinguished by the greater length of the rostrum, and 

 the duplex character of the lateral spines. 



St. Thomas. A. H. Kiise. 



Pericera cornuta. 



Pericera cornuta M. Edw., Hist. Nat. des Crust., ii. 355. Illust. Cuv. 

 Regne Anim., pi. xxx. f. i, Gibbes, Proc. Am, 

 Assoc. 1850, p. 172. 



This species is j^robably generically distinct from the trian- 

 gular JPericeroB. It was found at Key Biscayne, Fla., by 

 Dr. Cooper. 



ARaptycllUS,* nov. gen. 



Carapax triangularis, latior quam longior ; marginibus lateralibus 

 antero-lateralibusque laminiformibus, supra bases pedum expansis ut in 



* ' A.vaKTV)(Oi, expanaus. 

 APRIL, 1S60. Ig Ann. Lyc. Nat. Hist. Vol. VII. 



